Personal water craft (PWC) vehicles, including hydrofoil devices, have enjoyed immense popularity in recent years. PWCs generally allow one, two or more riders to sit, kneel or stand on the craft and to ride across the surface of a body of water. The popularity of PWCs is also attributable to the considerations that they are less expensive than traditional power boats, are more easily transported over land by smaller trailers, and storage and maintenance of the PWCs is generally simpler than with full size power boats.
Hydrofoils are appended to sailboards for the purpose of increasing speed or improving handling characteristics, or both. Higher speed comes essentially for free, since submerged hydrofoils can easily provide adequate lift while operating at much lower drag than planning hulls. The problem in the design of hydrofoil sailboards is that of providing rapid automatic corrective response to a number of destabilizing hydrodynamic effects, so that the sailor is able to control the craft.
U.S. Pat. No. 4,517,912 to Jones discloses a control means for hydrofoils for a sailing catamaran in which the attitude of a main foil is to be controlled by the depth of submersion of a smaller sensing foil, in consequence of which, the depth of the main foil, and hence the height of the craft itself, are kept constant. Jones states that his sensing foil should track at a small depth below the surface based on the analysis on the incorrect equilibrium depth expectation However, Jones does not teach or disclose anything related how to automatically generate corrective response to a number of destabilizing hydrodynamic effects to enable the sailor to control the hydrofoil.
U.S. Pat. No. 4,579,076 to Chaumette discloses a mechanism similar to Jones for automatic height regulation of individual hydrofoil elements. In both devices, because of the short horizontal distance between the sensing foil and the foil it controls, control will tend to be abrupt. This abruptness will become especially acute in waves.
Therefore, there remains a need for a new and improved motorized hydrofoil device with automatic stability control to generate corrective response to various destabilizing hydrodynamic effects to increase the stability of the hydrofoil device.